Electric governor switch



I Jan. 25, 1927. f y 1,615,365

' c. c. FARMER ELECTRIC GOVERNOR swITGH Original Filed June 15, 1922 INVENToR v(DLn/Dri C.`r'ARMER ATTORNEY Patented Jan. 25, 1927.

UNITED STATES 1,615,365 PATENT OFFICE.

CLYDE C. FARMER, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE WESTING- HOUSE AIB BRAKE COMPANY, 0F WILMERDING, PENNSYLVANIA, A CORPORA- TION 0F PENNSYLVANIA.

ELECTRIC GOVERNOR SWITCH.

Original application filed June 16, 1922, Serial No. 568,714. Divided and this application filed May 28,

This invention relates to electric pump governors and the principal object of the invention is to provide an improved pump governor of the type shown in Patent No. 1,169,305 of Walter V. Turner, dated January 25, 1916.

This case is a division of my original application, Serial No. 568,714, tiled June 16, 1922.

In the accompanying drawing, Fig. 1 is a central sectional view of an electric pump governor embodying my improvements, and Fig. 2 a section on the line 2-2 of Fig. 1.

As shown in the drawing, the electric pump governor may comprise a pipe bracket l to which is applied a casing 2. Said c asing contains a cylindrical bushing 3 forming a piston chamber 4 for a switch piston 5 having a cored stem 6 carrying at the outer end connected switch contacts 7.

For controlling the operation of the piston 5, a regulating device is provided comprising a cut-in and a cut-out portion, the cut-in portion comprising a piston 8 carrying a valve 9 and subject to the pressure of an adjustable coil spring 10. The cut-out portion may comprise a piston 11 having a valve 12 and subject to the pressure of an adjustable coil spring 13.

Before describing the particular improvements involved in the construction I will describe the general operation of the governor.

Assuming the springs 13 and 10 to have been adjusted to the respective desired cutting out and cutting in pressures and that the compressor is running, the pressure of Huid compressed by the compressor which is delivered to the usual main reservoir and which I will hereinafter term the main reservoir pressure, is supplied to the seated area of the valve 12 as well as to the seated area of the valve 9 through pipe 14, passage 15, chamber 16, to passage 18, and thence to passage 19, which leads to the seated areas of said valves.

When the main reservoir pressure acting on the seated area of the cut-out valve 12, slightly exceeds the pressure of the spring 13, the valve 12 will be lifted from its seat, exposing the full area of the piston 11 to main reservoir pressure, thus causing a quick ositive opening movement thereof. With tlie valve 12 open, main reservoir pres- Seral No. 641,903.

sure is supplied through passage 20 to the outer area of the cut-in piston 8 and since mam reservoir pressure now acts on the full area of the piston 8, the seated area of the valve 9 having been previously subject to main reservoir pressure, the piston 8 will be instantly shifted to its upper seat 21, closing communication through passage 22 from switch piston chamber 4 to the atmosphere and opening communication for supplying fluid at main reservoir /pressure to piston chamber 4 through port 23 and passage 22.

The main reservoir pressure acting on. switch piston 5 then shifts the piston so as to break the circuit of the compressor motor by separating the contacts 7 from the contacts 24 which are in circuit with the motor. At the same time, fluid at main reservoir pressure is supplied through port 25 in piston 5 to the opposite side of the piston and flows through port 26 into the hollow stem 6. When the piston 5 is shifted, ports 27 are uncovered by the movement of the stem 6, as the contacts 7 separate from the contracts 24, thus directing a stream of air onto the separating contacts to serve as a pneumatic arc blowout. When the piston 5 completes its outward travel, the annular bead 28 on the piston 5 engages a seat 47, thus preventing the further escape of main reservoir pressure.

Movement of the piston 5 to its cut-out position also uncovers port 29, so that fluid atmain reservoir pressure is supplied throughpassa-ge 30 to the spring chamber 31 of the cutout portion of the governor. 'Fluid pressures on opposite sides of piston 11 being thus equalized, the spring 13 will act to return the piston 11 and valve 12 to its seat. After the valve 12 seats, main reservoir pressure will continue to be supplied to the piston chamber 4 through passage 19, past the open valve 9 and through port 23 and passage 22.

The switch piston therefore remains in its cut-out position until the main reservoir pressure reduces to a point slightly less than the pressure of the spring 10 and then the cut-'in piston 8 moves to its position seating the valve 9. This closes communication through which fluid at main reservoir pressure is supplied to the switch piston 5 and at the same time the piston chamber Ll is connected to the atmosphere, through passage 22, spring chamber 32 and exhaust passage 33. Spring then returns the piston to its cut-in posit-ion, in which the cont-acts i" eng c the contacts Q4 and close the circuit ot t e motor which operates the compressor. it the same time, the spring chamber 3l is connected to the atmosphere through passage 30, passage 35, spring chamber 32 and passage The piston 'll to its eat at this time only by the pressure oil the spring 13, so that the cut out valve 12 can now litt trom its seat whenever the main reservoir pressure slightly exceeds the pressure of the regulating spring i3.

ln order to adjust the tension orn the springs i() and 13, cach spring contains a rod 36 having screw threads for an adjusting nut 3'4". Said nut is made lobe shaped as shown in s so tlatthe nut cannot rotate when the rbd i, turned. Each rod is adapted to malte a leal; tight seat within the sinn provided with a c liar A ig chamber and a screw threaded es: ension of each rod is provided with a nut 39. The tension ot the regulating spring iL c teinally adjusted by loosening the nut and turning the rod 36 by means oi a screw driver inserted in the slot e0.

is the rod is turned, the adjusting nut 3T moves up or down according to the direction in which the rod is turned and the tension or' the regulating spring is thus varied as desired. lfi'hen the desired adjustment is secured, the nut is s rewed down to tirinly hold the rod 313 and nut 3T in the adiusted position and at the same time makes a leal; tight goint ne collar r separate valve seat section il is provideo. i'or the valve i2 and a separate valve seat portion e2 is provided tor the valve 9, so that maintenance is facilitated by providing for quick removal for cleaning and replacing worn or damaged valve seats.

Screws d6 s rve to he d the seat sections all and in place, said screws being oppositely disposed but not diametrically opgosite, so that each seat can only be replaced in a particular l osition of adjustment as determined by th ff' Each contact :2L s connected to and sup- Lsorted by a sprl: a projection le oi' the sning serva as a stop to limit lateral movement the contact and a stop #l5 being provided to limit the vertical movement thereof. lllhile providing the desired flexibility, the above contact construction prevents the contact lingers 'l' from catching when cutting in.

aWhen the switch contact portion of the electric compressor governor is enclosed by the usual hood (not shown) it has been found that gases formed by arcing between the switch contacts will accumulate in the hood in spite of the Ventilatingopenings leading from the enclosed space to the atmosphere. These gases tend to increase the conductivity ot the gap i'ormcd by the separation oit the switch contacts and consequentlv the tendency to arcinpis increased. In drder to reduce this etllec, to a minimum, the exhaust air passage 83 'from the regulating portion o'ithe governor is connected tothe space adjacent to the switch contacts, so that air is blown into the enclosed space when the cut-in piston S moves the valve 9 to its seat and opens connnunication for venting air 'from the switch piston 5 to the passage Air thus supplied to the enclosed space tends to scavenge the same of the objectionable gases above referred to.

Having now described my invention, what l claim as new and desire to secure by Letters Patent, is

l. ln an electric pump governor, the combination with a piston and stem carrying switch contacts, ot a yielding contact adapted to engage each switch contact and having a hoolr at one end, a spring member secured to said yielding contact and' bent to form an open ended loop with saidl contact, the endA or the Contact hook overlapping the end oit said member, to thereby limit the lateral movement or" said yielding contact.

2. In an electric pump governor-,the combination with a piston and stem carrying longitudinally movable switch contacts, of a laterally movable yielding contact adapted to engage each switch contact and having a hoolr at one end, a spring member secured to said yielding contact', a support l'or said member, and a stop carried by said support and adapted to be engaged by the end'of said hooi; for iimiting the vertical movement of said yielding contact.

3. ln an electric pump governor, the combination with a piston and stem carrying switch contacts, or' a yielding contact adapted to engage each switch contact and having` a hook at one end, a spring member secured to said yielding contact and formed to entend into said hook to thereby limitthe lateral movement of said yielding contact,

a support -for said spring member, and a stop carried by said support and adapted to be engaged by the end of said hook for limiting the vertical movement of said yielding contact.

el. In an electricpump governor, the combination with a piston operated by fluid under pressure, a hollow stem carried by said piston, stationary contacts, and movable contacts carried by said stem lor engaging the stationary contacts, or a port through said piston for supplying fluid under pressure to said hollow stem and ports opened upon movement oi the piston by lluid under pressure :tor supplying tluid under' pressure trom said hollow stem to said contacts.

5. In an electric pump governor, the combination with a piston and switch contacts 10 bination with a piston and switch contacts operated thereby, of a regulating portion operated thereby, of a regulating portion having a cut-in piston operated upon movefor controlling the fluid pressure on said ment to the cut-in position for ventin fluid 5 piston and operable upon movement to its from the switch piston to the space a jacent cut-in position for venting fluid from said the switch contacts. 15 switch operating piston to a passage leading In testimony whereof I have hereunto set to the space ad]acent said switch contacts. my hand.

6. In an electric pump governor, the com- CLYDE C. FARMER. 

